package com.code.leetcode.pass;

/**
 * @author codeDorado
 * @version 1.0
 * @date 2020/7/22 16:31
 * https://leetcode-cn.com/problems/regular-expression-matching/solution/dong-tai-gui-hua-zen-yao-cong-0kai-shi-si-kao-da-b/
 * 因为看不懂导致之后再多来几次，这次我们遇到高手了
 */
public class The10_dp {
    public boolean isMatch(String s, String p) {
        int m = s.length();
        int n = p.length();
        boolean[][] dp = new boolean[m + 1][n + 1];
        dp[0][0] = true;

        for (int i = 0; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (p.charAt(j - 1) == '*') {
                    dp[i][j] = dp[i][j - 2];
                    if (matches(s, p, i, j - 1)) {
                        dp[i][j] = dp[i][j] || dp[i - 1][j];
                    }
                } else {
                    if (matches(s, p, i, j)) {
                        dp[i][j] = dp[i - 1][j - 1];
                    }
                }
            }
        }
        return dp[m][n];
    }

    public boolean matches(String s, String p, int i, int j) {
        if (i == 0) return false;
        if (p.charAt(j - 1) == '.') return true;
        return s.charAt(i - 1) == p.charAt(j - 1);
    }

}
